Connect Aspire apps to Dapr sidecars

⭐ Community Toolkit

This page describes how an app connects to the Dapr sidecar attached to it. For sidecar and component configuration in the AppHost, see Set up Dapr resources in the AppHost.

Connection properties

The hosting integration injects these environment variables into an app resource that has a Dapr sidecar:

Environment variable	Description
DAPR_HTTP_PORT	Port for the sidecar’s HTTP API
DAPR_GRPC_PORT	Port for the sidecar’s gRPC API
DAPR_HTTP_ENDPOINT	Full endpoint for the sidecar’s HTTP API
DAPR_GRPC_ENDPOINT	Full endpoint for the sidecar’s gRPC API

These variables are added in run mode. Pick the HTTP or gRPC endpoint that matches the SDK transport you configure.

Connect from your app

Each example uses the sidecar endpoint injected into the app resource.

C#

Install the official 📦 Dapr.Client package:

.NET CLI

.NET CLI — Add Dapr.Client package

dotnet add package Dapr.Client

Program.cs (C# file-based app)

Program.cs

#:package Dapr.Client@*

PackageReference (*.csproj)

XML — Add Dapr.Client package reference

<PackageReference Include="Dapr.Client" Version="*" />

Program.cs

using Dapr.Client;

var endpoint = Environment.GetEnvironmentVariable("DAPR_GRPC_ENDPOINT")
    ?? throw new InvalidOperationException("DAPR_GRPC_ENDPOINT is not set.");

using var daprClient = new DaprClientBuilder()
    .UseGrpcEndpoint(endpoint)
    .Build();

var product = await daprClient.GetStateAsync<string>(
    "statestore",
    "product-1");

ASP.NET Core apps can instead install 📦 Dapr.AspNetCore and register DaprClient with dependency injection.

TypeScript

Install the official Dapr JavaScript SDK:

Terminal

npm install @dapr/dapr

index.ts

import { CommunicationProtocolEnum, DaprClient, HttpMethod } from '@dapr/dapr';

const endpoint = new URL(process.env.DAPR_HTTP_ENDPOINT!);
const client = new DaprClient({
  daprHost: endpoint.hostname,
  daprPort: endpoint.port,
  communicationProtocol: CommunicationProtocolEnum.HTTP,
});

const response = await client.invoker.invoke(
  'catalog-api',
  'api/data',
  HttpMethod.GET
);

Python

Install the official Dapr Python SDK:

Terminal

pip install dapr

app.py

import os
from urllib.parse import urlparse

from dapr.clients import DaprClient

endpoint = urlparse(os.environ["DAPR_GRPC_ENDPOINT"])

with DaprClient(address=endpoint.netloc) as client:
    response = client.invoke_method(
        app_id="catalog-api",
        method_name="api/data",
        http_verb="GET",
    )
    print(response.text())

Go

Install the official Dapr Go SDK:

Terminal

go get github.com/dapr/go-sdk/client

main.go

package main

import (
    "context"
    "fmt"
    "net/url"
    "os"

    dapr "github.com/dapr/go-sdk/client"
)

func main() {
    endpoint, err := url.Parse(os.Getenv("DAPR_GRPC_ENDPOINT"))
    if err != nil {
        panic(err)
    }

    client, err := dapr.NewClientWithAddress(endpoint.Host)
    if err != nil {
        panic(err)
    }
    defer client.Close()

    response, err := client.InvokeMethod(
        context.Background(),
        "catalog-api",
        "api/data",
        "get",
    )
    if err != nil {
        panic(err)
    }

    fmt.Println(string(response))
}

See also

• Dapr service invocation
• Dapr SDKs
• Set up Dapr resources in the AppHost